Device for withdrawing brake air from diesel engine cylinders



June 29,1943. SCHWAIGERQ DEVICE FOE. 'ITHDRIING BRAKE AIR FROM DIESEL ENGINE CYLINDERS Filed larch 29, 1940 I Kar| Schwaiaer \NVENTQE. E (QmwMx *RXQAT 'Y" Patented June 29, 1943 DEVICE FOR WITHDRAWING BRAKE AIR" FROM DIESEL ENGINE CYLINDERS Karl Schwaiger, Gaggfinau, Baden, Germany; vested in the Alien Property Custodian Application March 29, 1940, Serial No. 326,610 In Germany March 29, 1939 4 Claims.

The invention relates to the withdrawal of air from the working cylinder of a combustion engine and theobject is particularly a simple, automatic and reliable loading of a compressed air reservoir, e. g. for air brakes, without an auxiliary compressor.

According to the invention the withdrawal of air from the working cylinder takes place dependent on the air pressure in the reservoir in such a manner that air is-withdravrn as long as the pressure in the reservoir is below a predetermined limit, but no further withdrawal of air is effected when the predetermined pressure is exceeded.

The invention is particularly applicable to air compressing engines, e. g. Dieselengines, but it may also be used in connection with mixture compressing engines whenever the withdrawal of a gas mixture can be effected without essential disadvantage.

The drawing shows,.by way of exampie, one embodiment of the invention.

Fig. 1 isa diagrammatical side view of the device, i

Fig. 2 shows the control cams and'the cooperating part of the transmissionon a larger scale, and" l Fig. 3 illustrates the mechanism shown in Fig. 2 in the condition which it assumes when a pre-' determined pressure in the reservoir or tank has been attained.

In the combustion engine 5, the crankshaft is indicated by 6, the cam shaft by l, a cylinder by 8 and the piston by 9. The valve I mounted in the cylinder head controls the connection of the compression chamber of the cylinder 8 with the tube l2 connecting the said chamber with the compressed air accumulator ll of a compressed air brake (not shown).

The air withdrawal or outlet valve I0 is actuated by a control cam 14 of the cam shaft I by means of the push rod l5 and the double-armed rocking lever IS. The push rod l5 actuates a tappet, consisting in a cylinder l8 guiding a piston IS. The said piston is pressed upon the cam l4 by a spring 20, bearing with one end against the lid I! and having a predetermined tension. The inner chamber of the cylinder I8 below the piston I9 is connected by the opening 2| and the tube 22 with the accumulator ll.

As soon as the pressure in the accumulator exceeds a predetermined value, the piston I9 is moved upwardly against the tension of the spring 20 by the cam I4, in such a manner that the control is cut off and the air outlet valve lil remains closed;

This is shown in Fig. 3 illustrating the camcontrolled linkage in inoperative condition in which it will leave the valve ll) closed.

It will be noted that the compressed air entering the auxiliary cylinder l8 from the tank ll through the conduit 22 and the opening 2| has lifted the auxiliary piston l9; compressing the spring 20.

Since the spring l3 tends to hold the valve H] in closed condition, it tends at the same time to rock the lever It in anti-clockwise direction and to lower the push rod I5. As will appear from Figs. 2 and 3, this push rod has a spherical head 23 bearing against a dish-shaped recess provided in the lid H which is firmly screwed into the threaded upper end of the auxiliary cylinder l8.

The cylinder constitutes a plunger slidably guided ina cylindrical bore 2'4 provided in a suitable bracketzfi of the crank case of the internal combus'tion engine. Thebore 24 has an internal shoulder 26 near its lower end constituting a seat on which the auxiliary cylinder l8 will rest under the pressure exerted by the rod it: when the linkage is in the disabled condition shown in Fig; 3.

As soon as the pressure in the tank I! drops below the predetermined limit determined by the biassedspring iii); the pressure exerted by the compressed air upon the annular shoulder 27 of the piston I9 is overcome by the force of the spring 29 thus lowering the auxiliary piston l9. As soon as the latter engages the cam 14, the

ressure exerted by the spring 20 upon the lid I! will lift the latter and the auxiliary cylinder i3 attached thereto until the internal shoulder 28 provided in the auxiliary cylinder l8 engages the annular shoulder 21 of the piston l9. When this engagement has taken place, the elements l8 and H! are kept by the spring 20 in the relative position shown in Fig. 2 constituting a rigid unit which may be regarded as part of the linkage and i will continue to act as a rigid unit until suflicient tract thus disabling the air has been fed through the conduit l2 to the tank H to raise the pressure therein above the predetermined limit. Then, the unit will conlinkage, as shown in Fig. 3/

When the engine is a four-cylinder engine, the cam I4 will be formed with a single-lobe adapted to open the valve I0 at the end of the compressing cycle just before fuel will be injected into the cylinder 8. During the three other cycles, that is to say, during the combustion cycle, the exhaust cycle and the intake cycle, the valve ill is kept closed by the spring l3.

Moreover, the cam shaft 1 is geared to the crank shaft 6 in a 2:1 ratio, if the machine is of the four-cycle type, as is well known in the art.

The quantity of air withdrawn from one or more of the cylinders 3 through the conduit I2 is so limited that it does not materially affect the efiiciency of the internal combustion engine. This is particularly true if the compressed air is needed only for the operation of brakes of a vehicle operated by the internal combustion engine, since the operation of brakes requires but a very limited amount of compressed air.

The pressure-responsive mechanism shown in Figs. 2 and 3 may be replaced by any other suitable means which are adapted, when the pressure in the tank surpasses a predetermined limit, to render the means opening the valve H3 inoperative.

My invention is capable of numerous other modifications within the scope of the appended claims. a

What I claim is: p v

1. The combination comprising an internal combustion engine of the type having at least one cylinder in which a gaseous medium is compressed by a piston and is then ignited, a tank, a conduit leading from said cylinder to said tank to supply some of said compressed medium thereto,

a valve controlling said conduit, means intermittently operated by said engine and adapted to positively open said valve at the end of the compressing stroke of said piston before the com- .pressed medium will be ignited, and means. re-

sponsive to the pressure in said tank and adapted, when the same surpasses a predetermined limit, to render said valve-opening means inoperative.

2. The combination comprising a Diesel en-' gine of the type having at least one cylinder in which air is compressed by a piston and fuel is then injected, a tank, a conduit leading from said cylinder to said tank to supply some of said compressed air thereto, a valve controlling said conduit, means intermittently operated by said engine and adapted to positively open said valve at the end of the compressing stroke of said piston before the fuel is injected, and means responsive to the pressure in said tank and adapted, when the same surpasses a predetermined limit, to render said valve-opening means inoperative.

3. The combination with a combustion engine including a working cylinder, a piston reciprocable in said cylinder, a crank shaft connected with said piston, and a cam shaft geared to said crank shaft, of a reservoir for pressure air, and a device for feeding said reservoir with pressure air from said working cylinder, said feeding device including a normally closed valve in the head of said cylinder, a pressure conduit leading from said valve to said reservoir, means including a cam on said cam shaft and a linkage controlled by said cam to open said valve for a predetermined period of each compression stroke of said piston, and means inserted in said linkage and responsive to the pressure in said reservoir to render said linkage inoperative when said pressure exceeds a predetermined limit.

l. The combination with a combustion engine including a working cylinder, a working piston reciprocable in said cylinder, a crank shaft and a cam shaft driven by said crank shaft, of a reservoir for pressure air and a device for feeding said reservoir with pressure air from said working cylinder, said feeding device including a normally closed valve in the head of said cylinder, a pressure conduit leading from said valve to said reservoir, and a control mechanism for said valve including a guide member, a hollow plunger with closed end walls slidable along said guide member, a piston axially reciprocable within said hollow plunger and dividing the inner space thereof into two chambers, a piston rod projecting through one of said chambers and passing with tight fit through an aperture in the corresponding end Wall of the plunger, a spring in the second chamber of said plunger urging said piston away from the corresponding end wall of the plunger, a fluid conduit connecting said first chamber with the fluid reservoir to cause displacement of said piston within said plunger against the action of said spring when the pressure in said reservoir exceeds a predetermined limit, a linkage connecting said plunger with the discharge valve, and a cam on said cam shaft arranged for cooperation with the free end of said piston rod to displace said piston, spring and plunger as a unit and to open the valve for a certain period of each com pression stroke of said working piston as long as the pressure in said reservoir is below said predetermined limit.

KARL SCHWAIGER. 

